ABSTRACT
Early studies of the effects of stimulus uncertainty (varying stimulus parameters from trial to trial) showed that knowing what to listen for has only minor effects (1–2 dB) on thresholds for the detection of single tones, or for the discrimination of tones by frequency (3–5 Hz) (Harris, 1952; Green, 1961; Creelman, 1973). One interpretation of these “non-effects” is that the central mechanisms of selective attention and memory play little or no role in auditory tasks….you hear whatever happens into your ear canal, so long as it is within the range of your (peripherally-determined) sensitivity and resolving power. An alternative possibility, addressed in this paper, is that auditory processing of complex sounds might be greatly influenced by cognitive mechanisms (or “psychological”, or “central”, ones, depending on your age), even though simple sounds are not; and that this difference is a consequence of the limited informational capacity of immediate auditory memory.
